The Samsung Galaxy S4 along with the S3 are two devices from Samsung that have been very popular. However many owners bought the handsets locked and this means they cannot move to another carrier. Thankfully an unlock code has leaked online allowing owners to unlock their device to take it to another carrier.
The leaked unlock code works with handsets that include the Samsung Galaxy S4 and the Samsung Galaxy S3 and more. When you use the unlock code you can then take the handset to a different carrier to get a better deal.
Get a new SIM card and then put this into your handset and then switch it back on. You should open your dial pad and you can then enter *#197328640#. You should then follow the steps below to unlock your handset.
 UMTS >  Debug Screen >  Phone Control >  Network Lock > Options  Perso SHA256 OFF.
Now you need to wait for 30 seconds and you can then head to the main menu and here you should see Network Lock. You can then choose  NW Lock NV Data INITIALLIZ and you should now have a handset that is unlocked.
The code works with the Samsung Galaxy S4, S3 and many other devices belonging to Samsung so try it.